IEC 61504:2017

Overview

IEC 61504:2017 - Nuclear facilities: Instrumentation and control systems important to safety - Centralized systems for continuous monitoring of radiation and/or levels of radioactivity defines the scope and expectations for centralized radiation-monitoring systems that have a direct role in achieving or maintaining radiation protection in nuclear facilities. It supplements IEC 61559‑1 and integrates the content of IEC 61559‑2, addressing radiation-monitoring functions that fall outside the remit of IEC 61559‑1. The standard focuses on systems used for radiation protection, environmental monitoring and information supply to control and safety systems.

Key topics and technical requirements

• Scope of application: centralized systems performing safety-important radiation and radioactivity monitoring in nuclear facilities.
• Primary functions covered:
  • Radiation protection of plant discharge and control of releases.
  • Interlock of control functions to prevent or mitigate accidental release of radioactive material.
  • Radiation and environmental monitoring to support monitoring and emergency response.
  • Provision of information to process control or safety systems for control or interlock actions.
• Integration and architecture: describes the integration of monitoring functions, including equipment that may be covered by other IEC standards, and supplements IEC 61559‑1 by incorporating IEC 61559‑2 content.
• Safety importance: targets systems with a direct role in radiation protection and ties monitoring outputs to operational and safety decision-making (e.g., interlocks, alarm and mitigation).
• Technical change highlights (2017 edition):
  • Formal supplementation of IEC 61559‑1.
  • Integration of IEC 61559‑2 material.
  • Expanded guidance on integrating functions and equipment across other IEC standards.

Applications and who uses it

IEC 61504:2017 is intended for:

• Nuclear I&C designers and system architects building centralized radiation monitoring systems.
• Safety engineers and licensing authorities assessing radiation protection measures and interlock logic.
• System integrators and suppliers of detectors, data acquisition and central processing units used in nuclear facilities.
• Emergency planners and operations staff who rely on environmental and radiation monitoring to support accident response.

Practical benefits include improved consistency in system classification, clearer requirements for integration with process control and safety systems, and a stronger foundation for designing monitoring systems that actively contribute to radiation protection.

Related standards

• IEC 61559‑1 (supplemented by IEC 61504:2017)
• IEC 61559‑2 (integrated into this edition)
• Other relevant IEC standards covering specific detectors, data acquisition, and communication interfaces as referenced by IEC 61504.

Keywords: IEC 61504:2017, nuclear instrumentation and control, radiation monitoring, centralized systems, radiation protection, interlock systems, environmental monitoring, IEC standards.